ASTB Notes

Wings

Primary airfoils of an aircraft

Airfoil

Anything designed to produce lift when moved through the air

Which edge of the wing is thicker?

Leading edge

Which surface has a greater curve?

Top surface

Where do wings connect?

Either side of fuselage

What are the 3 wing positions?

High, medium, low

Cantevallier Wing

sufficient internal supports to maintain wing position

Semi-Canteveilliar Wing

requires additional external support structures to keep in position

Trailing edge of wing has two control surfaces attached by means of a hinge

Flaps, Ailerons

By raising and lowering what, the pilot can roll the plane

By raising and lowering the ailerons, the pilot can roll the plane

When will the plane roll?

When the ailerons are facing opposite directions

How are ailerons positioned while cruising

They are level with the wing of the plane

When will both extend, why?

During takeoff/landing, it increases lift

Wingspan

Distance from wingtip to wingtip

Chord

Distance from leading edge to trailing edge (divided wing into upper/lower surfaces

Planform

View of plane from above

Camber line

Line that runs from the inside of the wing splitting it into equal halves based on thickness

Camber

curvature of the airfoil

Heavily curved = ?

High camber

Dihedral Angle

When wings are not attached horizontally to the wing

Positive Dihedral

Wings angled above the horizontal plane (keeps plane stable during rolls, encourages return to natural position)

Why don’t most jets fly with a positive dihedral angle?

It reduces maneuverability, most jets will have wings stay horizontal or slightly down ahedral

Straight wing

Found on gliders. sailplanes, or low speed aircraft (round, rectangle, or tapered shape)

Sweep Wing

Better for high speed, and harder to handle at low speed, decreased drag, higher angle of sweep for higher speeds, more extreme sweep needed for takeoff/landing

Delta Wing

Leading edge has higher sweep angle, where trailing edge is nearly straight

What components are part of the fuselage?

Cockpit, cabin, cargo are (can include wings/landing gear)

Truss

Monocoque

Stabilizers

fixed surfaces from the back end of the fuselage

Elevators

Positioned on the trailing edge of the horizontal stabilizers, pilot can control them to move nose up/down

Rudders

Connect to the trailing edge of the vertical stabilizers, pilot can control them to move the nose left/right usually with the help of ailerons

Trim Tabs

Small surfaces along the trailing edge of the rudders, elevators, and ailerons used to make smaller adjustments

Tricycle Landing Gear

Two wheels under mid part of plane, third under nose

Conventional Landing Gear

Two wheels positioned under airplane body. third placed under tail

Powerplant

Part of plane that supplies thrust

Propeller Plane: fixed-pitch blade

Blade angle cannot change

Propeller Plane: Variable-pitch blade

blade angle can be adjusted to alter thrust

Engine of a propeller

Engines power propeller blades to turn crankshafts, crankshafts turn propeller blades (also responsible for powering planes electrical system)

Flight Envelope

A graphical representation to help pilots understand the limitations/flight parameters to ensure a safe flight

4 forces a pilot must control

Lift, weight, thrust, drag

Basic Weight

Weight of plane with all basic controls (with plane throughout whole flight)

Operating Weight

Basic weight plus crew and nonexpendable

Gross Weight

Weight with all contents at any given time

Zero Fuel Weight

Weight of plane with no useable fuel

Lift

The upwards force of air pressure on an aircraft, primarily the wings to achieve and maintain altitude

Requirements for lift

Plane must be traveling forward at a considerable speed

What happens if wings tilt too far what will happen?

Airflow over the wing will decrease, causing a sudden drop in altitude and/or control of the plane (may be avoided by decreasing angle of attack)

Thrust

speed required for generating lift (generated by power plant)

Drag

Resistance to forward movement, increases with airspeed

Parasite Drag

Combination of several types of drag: skin friction, form, interference

Induced Drag

Drag resulting from all wings generating lift

Flying into headwind

Experience GREATER lift and drag

Flying into a tailwind

Experience LESS lift and drag

Higher air density

low temp, high pressure, high humidity (produce greater lift and drag)

Longitudinal axis

from tip of nose to tailaL

Latitudinal axis

From wingtip to wingtip

Vertical axis

Through center of the plane

Roll

Rotation across the longitudinal axis (ailerons)

Pitch

Rotation across the lateral axis (elevators)

Yaw

Rotation across the vertical axis (rudders)

Joystick/Yoke (ailerons)

Pushing the stick left raises the left aileron (wing) and raises the right, pushing the stick raises the right and lowers the left

Joystick/Yoke (elevators)

Pulling back raises the nose, pushing forward lowers it

Rudder pedals

Push left pedal, rudder swings left and nose turns left

Push right pedal, rudder swings right and nose turns right

Throttle

Controls amount of thrust produced by the engines

Secondary flight control surfaces

Flaps, Spoilers, Trim systems

Flaps

connected to trailing edge of wings, raised and lowered to adjust thrust and drag (meant to reduce stall speed)

Spoilers

Attached to wings to increase drag and reduce lift, can be useful in a roll to reduce adverse yaw

Trim systems

Used to ease work of pilot, attached to one or more primary control surfaces (adjusted with small wheel or crank in cockpit)

Straight-and-level flight

Require frequent adjustments to stay straight, similar to a car

3 types of turn

Shallow, medium, deep

Throttle in a turn

set to achieve proper speed for certain type of turn

Ailerons in a turn

Bank the wings

Elevators in a turn

raise the nose to establish rate of turn

Rudders

Employed to counter any undesired yaw resulting from other control effects or desired yaw

Shallow turn

Less than 20 degrees, plane will try to destabilize naturally, so pilot must keep enough pressure on the stick to prevent coming out of the bank early

Medium turn

20-45 degrees, most planes will stay in this position until the pilot makes an adjustment

Deep turn

Greater than 45 degrees, most planes will try to increase the banking angle so the pilot must apply enough pressure to the stick to counter it

Why does the pilot pull back on the stick during a turn?

To ensure the nose stays up (usually the deeper turn the more pulling required), also why they must apply the same amount of rudder pressure as the turn being made

How to initiate a climb?

The nose must be pointing upwards, properly with enough thrust so it doesn’t stall

Descending

Involves two factors: pitch and thrust, by angling the nose downwards the angle of attack and amount of lift decrease and by pulling the throttle back the pilot reduces the amount of speed

Glide

Controlled descent where no power is used, managed by balancing forces of lift and gravity

What are the 4 fundamentals of a helicopter?

Lift, weight, thrust, drag

How is thrust applied to a helicopter?

Most thrust is applied vertically

How does a helicopter generate lift?

Rapidly spinning propellers with blades angled slightly downwards to force air down

What is torque control?

Because the main propeller generates so much torque, it exerts the same force on the fuselage, so the back propeller is used to stabilize it In flight.

What does manipulation of the tail rudder on a helicopter do?

Can affect heading

What conditions are required for consistent speed in a horizontal path?

Lift is equal to weight, and thrust is greater than drag

What conditions are required for an increase in altitude in a helicopter?

lift is greater than weight

What are the 3 main controls of a helicopter

Collective, Cyclic, and Directional control system

What is the cyclic?

Controls latitudinal and longitudinal movement of aircraft, by adjusting the tilt of the main rotor (moving the stick forward pushes the rudder ahead, causing the plane to move forward)

What is the collective?

Tube running from the cockpit floor to the left of the pilot, has a candle that can be lowered/raised to change pitch and throttle that can be turned to change engine torque.

What is the directional control system?

Pair of pedals pilot can use to change the pitch of the tail rotor blades.

How does the directional control system work?

Pressing on either of the pedals will cause the rotator blades to exert more or less force on the fuselage, which will change the heading of the helicopter.

How will a helicopter pilot use all 3 controls?

Must use all 3 at the same time, the cyclic and collective adjust the action of the main rotor, the the adjustment of the tail rotor compensates for it.

What happens if a helicopter loses power?

Pilot must rely on autorotation to land safely

What is autorotation?

the natural spinning of the main propeller with airflow, generating enough torque to use the tail rudder

What must you do if the speed of the main rotor increases?

Must increase the amount of force on the tail rotor so the fuselage doesn’t spin

Translational lift

Extra lift a helicopter experiences when traveling in a forward direction

Coriolis force

the increase of spinning speed when the weight of the object is moved towards the rotational center

Transverse flow effect

If the main rotor increases the airflow over the rear part of the main rotor disc, then the rear part will have a similar angle of attack